GL_OES_fixed_point#

Supported Hardware#

Series5, Series5XT, Series6, Series6XE, Series6XT

Valid APIs#

OpenGL ES 1.x

Description#

This extension provides fixed point functions for hardware that supports the OpenGL ES 1.x common profile but has inefficient floating-point support. The functions provided are equivalent to the Common-Lite profile and are denoted by ending in an “x” instead of an “f” for floating-point functions. Fixed point values are unsigned integers that are scaled to a S15.16 representation. The S15.16 representation means that there is one sign bit, the top 15 bits represent integer values, and the bottom 16 bits represent values below zero. In essence, it represents a signed short with 16 bits of sub-zero values.

Example#

// Use the fixed-point version of a function to scale by 1.0, 0.5 and 2.0 in the x, y and z
// axes respectively. The value "65536" is effectively treated as 1.0.
GLfixed x = 65536;
GLfixed y = 65536 / 2;
GLfixed z = 65536 * 2;
glScalex(x, y, z);